Shutting down an all-girls residential school puts the disabled students at risk of physical and sexual abuse, a study shows.

Nelson's Salisbury School board is taking Education Minister Hekia Parata's decision to close the school to court.

Parata wants to transform all boys Halswell Residential College in to a co-educational facility and move the students there. The High Court in Wellington will hear the case later this month.

But Fairfax Media has obtained a submission written on behalf of the school in September before the final decision was announced. It warns the post-primary school aged girls who attend the school are ''uniquely vulnerable'' to abuse.

Placing them in a co-ed school exposes them to increased risk. More than 250 students who attended the school between 1994 and 2012 had a history of abuse, drug and alcohol issues or exposure to domestic violence, a review of more than 400 school files shows.

Almost half (193 pupils) aged between 11 and 18, talked to school counsellor about incidents of sexual abuse prior to their admission to Salisbury. And an earlier study by respected Australian expert Freda Biggs found more than 40 per cent of the girls were victims of rape or sexual abuse.

''They are dealing with the intense emotional issues associated with adolescence, in addition to their existing complex intellectual impairments,'' the submission says.''These figures confirm the vulnerability of post-primary girls with intellectual impairment to all forms of abuse, and underscore the serious issues associated with exposing these students to increased risk of abuse in a co-educational residential environment.''

A preliminary study of parents shows more than two thirds (68 per cent) would not send their daughters to a co-ed school because of fears for their ''physical and sexual safety.''

Disestablishing the school might then deny residential care to those who need it. The submission also shows the school roll was ''managed down'' compared to Halswell.

Green MP Catherine Delahunty says while her party are committed to inclusion for all disabled people, Parata should reconsider.

''The reality is Salisbury have shown that up to 40 per cent of those girls have been abused. That is a terrifying statistic. From my understanding Salisbury worked very hard to strengthen those young women so they are confident and able to be safer in what is an unsafe world for them.

''We would be wise to consider what Sailsbury are trying to tell us and instead of setting arbitrary goals and being romantic about what is being offered we need to be real about the options that Sailsbury have put forward.''

Both Parata and the school are unable to comment while the matter is before the court.

Salisbury is earmarked for closure in January along with McKenzie Residential School in Christchurch.